<template>
  <v-chart :forceFit="true" :height="height" :data="data" :scale="scale" :onClick="handleClick">
    <v-tooltip :showTitle="false" dataKey="item*percent" />
    <v-axis />
    <v-legend dataKey="item" />
    <v-pie position="percent" color="item" :v-style="pieStyle" :label="labelConfig" />
    <v-coord type="theta" />
  </v-chart>
</template>

<script>
const DataSet = require('@antv/data-set');
import { ChartEventMixins } from './mixins/ChartMixins';

export default {
  name: 'Pie',
  mixins: [ChartEventMixins],
  props: {
    title: {
      type: String,
      default: '',
    },
    height: {
      type: Number,
      default: 254,
    },
    dataSource: {
      type: Array,
      default: () => [
        { item: '示例一', count: 40 },
        { item: '示例二', count: 21 },
        { item: '示例三', count: 17 },
        { item: '示例四', count: 13 },
        { item: '示例五', count: 9 },
      ],
    },
  },
  data() {
    return {
      scale: [
        {
          dataKey: 'percent',
          min: 0,
          formatter: '.0%',
        },
      ],
      pieStyle: {
        stroke: '#fff',
        lineWidth: 1,
      },
      labelConfig: [
        'percent',
        {
          formatter: (val, item) => {
            return item.point.item + ': ' + val;
          },
        },
      ],
    };
  },
  computed: {
    data() {
      let dv = new DataSet.View().source(this.dataSource);
      // 计算数据百分比
      dv.transform({
        type: 'percent',
        field: 'count',
        dimension: 'item',
        as: 'percent',
      });
      return dv.rows;
    },
  },
};
</script>
